The biochemical mechanisms by which glucagon stimulates hepatic mitochondrial function will be further studied. The effect of varying monovalent cations in the assay medium used for respiratory studies will be determined. The lipid composition of the inner mitochondrial membranes will be studied to see if glucagon treatment causes any change in the phospholipids present. Reconstitution of partial reactions of electron transport with phospholipids from control and glucagon treatments will be attempted to determine whether the phospholipids have been changed functionally after glucagon treatment. Isolated hepatocytes will be used to prepare radiolabeled protein and lipid fractions to see if glucagon treatment affects the labelling pattern. Cellular calcium movements as affected by alpha-adrenergic agents, vasopressin, and glucagon will be studied.